To determine the effect of daily oral administration of 5 mg of alendronate and 10 mg of alendronate relative to daily oral administration of placebo on lumbar spine BMD during Years 6 through 10 of therapy; and to obtain data on the safety and tolerablity of daily oral administration of 5- and 10-mg doses of alendronate for 3 years in postmenopausal osteoporotic women previously treated with 5 or 10 mg daily alendronate for 7 years.